This subproject is one of many research subprojects utilizing the resources provided by a Center grant funded by NIH/NCRR. Primary support for the subproject and the subproject's principal investigator may have been provided by other sources, including other NIH sources. The Total Cost listed for the subproject likely represents the estimated amount of Center infrastructure utilized by the subproject, not direct funding provided by the NCRR grant to the subproject or subproject staff. Ebola virus causes a 50-90% lethal hemorrhagic fever. The virus is divided into five separate species, of which two (Zaire ebolavirus and Sudan ebolavirus) cause almost all of the major human outbreaks. The Zaire species and the Sudan species are antigenically distinct. Hence, any vaccine or therapy must include both species in order to have broad range utility in the field. We have recently determined the crystal structure of the viral surface glycoprotein from the Zaire species, bound to a rare antibody from a human survivor. This structure has yielded tremendous insights into viral infection and ways in which we can provide protection against the Zaire species of the virus. Now, we wish to determine a crystal structure of GP from the Sudan species so that we can provide the necessary template for development and improvement of Sudan-reactive vaccines and therapeutics for broad-range utility. Crystals of Sudan GP in complex with a novel antibody have been obtained and will be screened for diffraction. In addition, we will screen crystals of proteins involved in Ebola virus assembly and replication, as well as crystals of the Lassa Fever virus surface glycoprotein.